A synopsis for an upcoming episode of The Flash promises a hotly-anticipated reunion between Barry Allen and Eobard Thawne, the Reverse Flash.

Per The CW, in "Armageddon, Part 4" Barry will be shocked when Thawne (Tom Cavanaugh) "returns in the most unexpected way, and with a tie to a loved one." The Scarlet Speedster will also receive some advice from Damien Darhk (Neal McDonough), but there's a catch to it. The synopsis also promises an epic showdown between The Flash and his arch-enemy, with special guest stars Batwoman (Javicia Leslie), Sentinel (Chyler Leigh) and Ryan Choi (Osric Chau).

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The supervillain team-up of Thawne and Darhk was promised back in August. Showrunner Eric Wallace spoke of Thawne's return to Central City, saying "So at the end of last season, Reverse-Flash -- he's a pretty pissed-off dude. Why? Because The Flash is faster now...If there's one question that 'Armageddon' answers, it's, 'Well, if you can't outrun your foe, what do you do to beat him? That's where Eobard Thawne will start in 'Armageddon.' That's really the question for him, and that question gets answered throughout all of Season 8, in weird and unexpected ways."

He added that while Thawne's ancestor and former Flash regular Eddie Thawne will return in Season 8, he won't appear in the first story arc of the season. "Well, first of all, to temper expectations, Eddie is not in 'Armageddon.' Eddie is part of a separate graphic novel," Wallace said. "We have three graphic novels this year in Season 8. Knock on wood if we can pull off this gargantuan feat, but they all spin out of 'Armageddon.'"

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Darhk's inclusion comes as a surprise to many fans. When last seen, the one-time supervillain seemed to be on a path to some sort of redemption, having reconciled with his daughter Nora and her new husband, Ray Palmer/the Atom. He was also dead and had resigned himself to spending an eternity in Hell. However, fans of the Arrowverse know that Darhk -- a man well-versed in both black magic and time travel -- is no stranger to escaping death, so his return to the land of the living isn't beyond the realm of possibility.

The full synopsis for "Armageddon, Part 4" reads as follows:

BARRY FACES OFF WITH EOBARD THAWNE – Barry (Grant Gustin) is shocked when Eobard Thawne (guest star Tom Cavanagh) returns in the most unexpected way, and with a tie to a loved one. Damien Darhk (guest star Neal McDonough) offers advice to Barry but there is a catch. An epic battle begins with Reverse Flash pitted against The Flash, Team Flash, Batwoman (guest star Javicia Leslie), Sentinel (guest star Chyler Leigh) and Ryan Choi (guest star Osric Chau). Chad Lowe directed the episode written by Lauren Barnett (#804). Original airdate 12/7/2021.

New episodes of The Flash air Tuesdays on The CW. "Armageddon, Part 4" airs Dec. 7 on The CW.

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Source: The CW